Lock key



P. W. OLSON May 9, 1939.

LOCK KEY Filed July 9, 1934 www Patented May 9, 1939 unirse stares maar ogs LOCK KEY ration of Michigan ApplicationJuly 9,. V1934, Serial No. '734,252

8 Claims.

This invention relates to lock keys, zand- -a main object of .the invention is to provide a key which is diicult to duplicate without the proper equipment, and which cannot be made by filing straight across the edges of the blade.

Another object of the invention is to provide a key with the corners cut away to form a central web with tumbler operating ledges at the sides of the key facing in the same direction as the edges thereof.

Another object of the invention is to provide such a key which is accurately'guided in the keyway; and to p-rovide a key which may be inserted either side up in the lock.

Other objects and advantages will become more apparent in the following description, taken with reference to the accompanying drawing, in which- Fig. 1 is a longitudinal cross section of a cylinder lock, with a key embodying this invention inserted therein;

Fig. 2 is a transverse section taken on the line 2--2 of Fig. 1;

Fig. 3 is a perspective view of the key; and

Fig. 4 is a view looking at the end of the key.

This invention relates to keys for locks. of the rotary cylinder type having a plurality of tumbler elements normally positioned to lock the cylinder against rotation in its casing. Locks of this general type are disclosed in my co-pending applications Serial No. 712,240 for Lock tumblers, filed February 20, 1934, and Serial No. 713,007 for Cylinder locks, led February 26, 1934, and now Patent No. 2,023,208.

The key E has a flat blade 8 rectangular in cross section which is insertable in the keyway 9 of the lock which comprises a housing I in which is rotatably mounted a tumbler cylinder Illa, in which said keyway is formed.

On each side of the keyway are provided transverse tumbler slots II having plate tumblers I2 slidably mounted therein. 'Ihe ends of the tumblers normally project into longitudinal grooves formed in the bore of the housing for locking the cylinder from rotating therein, as will be understood by anyone acquainted with this art.

The tumblers and slots are wider at one end than at the other, and are stepped to provide shoulders I3 and I3a, in the tumbler and slot respectively, between which coiled springs I4 are compressed for pressing the larger ends of the tumblers outwardly from the cylinder.

On the inner sides of the tumblers are formed lugs I5 which project into the keyway. The inner edges of the tumblers are also shouldered asshown, so ythat after the tumblers are iinserted into the ends of the slots, they are retained in thecylinder'by longitudinally insertable bars I8, which Aalso define the upper and Yflower sides of the-keyway. 'Thebars -I-8 lare secured in positionbyfa cover I9Uwhich -is iixedl-y secured to the outer end of thefhousing lill.

The corners of the key-blade 8 are cut away to provide ledges 20, 2I, 22 and 23, the ledges on the opposite sides of the blade being separated by central Webs 24 which extend to the edges of the blade and fill the space between the upper and lower sides of the keyway, thus accurately guiding the key longitudinally in the slot.

'Ihe key being inserted in the position shown in Fig. 2, the conformation of the ledges Ztl and 23 is made so that when the key is in position the lugs I5 are positioned so that the tumblers are withdrawn completely into the cylinder and the cylinder is then free to turn.

By constructing the lock so that the tumblers on the opposite sides of the keyway are moved in opposite directions, the other ledges ZI and 22, have no function in this position of the key; but by making these ledges conform to the diagonally opposite ledges, the tumblers may be correctly operated by these ledges when the key is turned the other side up.

The lugs I5 are of course formed in different locations on the edges of the tumblers for varying the locks, with the result that the tumbler operating ledges which are directly opposite, such as 20 and 2l, are, at least in some portion, in overlapping relation. Therefore it is impossible to form the key by hand filling. Also if the web is cut away, the key-blade would not be properly positioned in the keyway.

Having thus described an illustrative embodiment, I claim as my invention:

1. A key for a lock having a keyway with tumblers slidably mounted on each side of the keyway, the tumblers on one side of the keyway being operable in one direction and the turnblers on the opposite being operable in the other direction, the key having central webs forming the edges thereof for positioning the key in the lock and convoluted longitudinally extending shoulders formed on each side of each of the webs, the diagonally opposite shoulders being of identical contours so that the key may be inserted either side up.

A lock key comprising a straight blade originally of rectangular section with the longitudinal corners cut away leaving a central web of full width but with irregular longitudinal projeotions at the sides thereof for operating the tumblers of the lock.

3. A lock key comprising a central web and irregular longitudinally extending tumblers operating projections on the lateral faces thereof, the projections on opposite sides of the key being separated by the web which forms the edges of the key for guiding and locating the key in a lock.

4. A lock key comprising a at blade with a central Web forming the edges thereof and having longitudinally extending projections with serrated projections projecting outwardly at either side of the web.

5. A key for a lock having a key-way with tumblers slidably mounted at either side of the key-way, the blade of the key comprising a. central web of uniform Width filling the key-way to position the key in the lock,` and tumbler operating projections formed on each side of the central portion of the web.

6. A key comprising a straight blade originally of rectangular cross section with each of the longitudinally extending corners thereof cut away at its side to form tumbler operating shoulders exposed at the sides of the key.

7. As an article of manufacture, a key for a cylinder lock of that type having two independently operable sets of tumbler elements arranged on opposite sides of the keyWay in the lock, said key including an operating portion, and two longitudinally extending unrelated cam surfaces formed at each side `of the key intermediate the opposite edges thereof to provide oppositely projecting webs tting in the keyway, said cam sur faces being adapted to operate the tumblers at opposite sides of the keyway in the lock.

8. As an article of manufacture, a key for a cylinder lock of that type having a plurality of tumbler elements at each side of the keyway in the lock, said key including an operating portion having a pair of cam surfaces at ea-ch side thereof, a cam surface at one side of the key corresponding With a cam surface at the other side of the key, and key-guiding portions or webs above and below the cam surfaces, whereby the key will operate the tumblers when eitherk PHILLIP W. OLSON. 

